The Basics of Nutrition
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“You are what you eat”
Food is your body’s fuel
Food is eaten
◦ It is broken down into simpler elements
◦ Energy is released and nutrients are used to help
build, repair, and maintain body cells
◦ By-products are discarded as waste
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These substances are best obtained from the
food you eat
The body needs elements from all 6 groups in
order to function properly and maintain good
health
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Carbohydrates
Fats
Proteins
Vitamins
Minerals
Water
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Where do they fit?
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Nectarine
Wheat bread
Trail mix
Water
Why wouldn’t an unlimited supply of only one
of these foods sustain life?
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I know, I know – who wants to learn chemistry
in HCR???
To understand the basics of nutrition, there
has to be some understanding of basic
chemistry – SORRY! 
No worries – we won’t get too crazy with it
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Your body and the foods you eat are
composed of chemical elements
Elements are the simplest substances from
which all matter is formed
◦ An atom is the smallest part of an element
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A molecule is the smallest amount of a
substance that has all the characteristics of
the substance
◦ Molecules are 2 or more atoms bonded together
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The atoms in a molecule may be all the same
element, or they may be different elements
When atoms of different elements bond
together, they form compounds
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5 of the basic nutrient groups are compounds
(combination of different elements)
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Carbohydrates
Fats
Proteins
Vitamins
Water
1 basic nutrient group is elements (simplest
substance)
◦ Minerals
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The essential nutrients from food are used to
◦ Build and repair body tissues
◦ Regulate all body processes
◦ Provide energy
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When provided with the proper nutrients,
your body can perform all of these functions
in harmony, which optimizes health, wellness,
and performance
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The body is made up of billions of cells
◦ Cells divide, producing 2 new cells each time, which
accounts for your growth
◦ New cells also repair damaged body tissues and
replace old cells
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All cells are formed with materials that come
from food
Therefore, your body needs proper amounts
of nutrients to help make new cells
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Periods of rapid growth require greater
amounts of nutrients
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Pregnancy
Infancy
Adolescence
Illness/injury recovery
Lacking proper nutrients during these periods
can negatively affect growth potential,
strength, health, healing, learning abilities,
and behavior patterns
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Mood?
Attitude?
Thinking?
Physical performance?
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The proper amounts and types of nutrients
keep body processes running smoothly
Examples of body processes that rely on
nutritional components
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Circulation of body fluids
Maintaining the correct acid-base level in the blood
Digestion
Absorption
Metabolism
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Food is a source of energy for performance
The quality of the food you eat affects how
your body will run
The more active you are, the more energy you
will need to fuel your body processes
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Chemical reactions that take place in your
cells release energy from nutrients that you
get from food
◦ Carbohydrates and fats are the main nutrients used
for energy
◦ Proteins can be used, but the body prefers to save
them for other vital functions
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Vitamins, minerals, and water do not provide
energy, but the body needs them to help
regulate the release of energy from carbs,
fats, and proteins
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Measured in units called kilocalories (kcal)
Commonly known as calories
Only certain nutrients provide energy
◦ 1 gram of carbohydrate = 4 kcal of energy
◦ 1 gram of fat = 9 kcal of energy
◦ 1 gram of protein = 4 kcal of energy
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Water, vitamins, and minerals do not yield
energy, and therefore do not have a calorie
content
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Alcohol does have a calorie content
◦ 1 gram of alcohol = 7 kcal of energy
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It is not considered a nutrient because:
◦ It does not promote growth (it inhibits)
◦ It does not maintain cells (it destroys)
◦ It does not repair tissues (it inhibits healing)
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Determining Energy Values
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The process by which your body breaks down
food, and the nutrients in food, into simpler
substances
◦ The blood can carry these simpler substances to the
cells for use in growth, repair, and maintenance
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Digestion occurs throughout the digestive system
through mechanical and chemical means
◦ Mechanical digestion – occurs when food is crushed and
churned
◦ Chemical digestion – occurs when food is mixed with
acids and enzymes
 Enzyme – a type of protein produced by cells that cause
specific chemical reactions
 In digestion, they cause food particles to break apart into
simpler substances
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The muscular tube through which food
passes from the mouth to the anus
Roughly 25-30 feet in length
Each section has different functions
Mouth → esophagus → stomach → small
intestine → large intestine
 Pg. 49
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Mastication (chewing) is the1st step in
digestion
Important mechanical digestive process as
chewed food is broken down more easily by
the body
Food is mixed with saliva in the mouth, which
helps to moisten, soften, and dissolve food
◦ Included in saliva is salivary amylase, an enzyme
which helps to break down starches
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Passageway from mouth to stomach
About 10 inches long
Food moves along this passageway through a
series of muscular squeezing actions called
peristalsis
Involuntary muscle action that is part of
mechanical digestion
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The stomach produces gastric juices to aid in
digestion
◦ Made up of acids, enzymes, and mucus
◦ Acids and enzymes break down food, and mucus softens
and lubricates chyme
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The gastric juices mix with the chewed food to
form chyme
The stomach can typically hold about a quart of
food
Food generally stays in the stomach for 2-3
hours, depending on the type of food
◦ Liquids leave first
◦ Fats leave last
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About 95% of digestion takes place here
Has 3 sections, and is roughly 20 feet in
length and 1 inch in diameter
Takes food about 5-14 hours to move
through the small intestine through
peristalsis action
The small intestine is aided by other organs
during digestion
◦ Pancreas – adds digestive enzymes
◦ Liver – adds bile for breaking down fats
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*Nutrient Digestion in the Small Intestine
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Also known as the colon
Main job is to reabsorb water
Very little digestion occurs here
About 5-6 feet long
Chyme stays in the colon for 1-3 days before
elimination
Solid wastes that result from digestion are
eliminated as feces
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*Food Breakdown
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Absorption is the passage of nutrients from
the digestive tract into the circulatory or the
lymphatic system
◦ Circulatory system – amino acids, monosaccharides,
minerals, and most vitamins
◦ Lymphatic system – nutrients from fats
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Most nutrients pass through the walls of the
small intestine
The small intestine is lined with tiny, fingerlike projections called villi
◦ Villi increase the surface area of the small intestine
and aid in absorption of nutrients
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Once digestion and absorption have taken
place, the circulatory system carries the
nutrients to individual cells
Metabolism is all the chemical changes that
occur as cells produce energy and materials
needed to sustain life
◦ Cells break down nutrients to release energy, which
is stored in the muscles as ATP
◦ The waste products created through cell
metabolism are eliminated through the kidneys,
lungs, and skin
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Eating Habits Affect Digestion
◦ Don’t eat too much or too little
◦ Eat a variety of foods in order to get all of the
required nutrients
◦ Include high-fiber foods to provide bulk and aid in
removing toxins
◦ Foods high in fat will take longer to digest as fats
are the last nutrient component to leave the
stomach
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Emotions
◦ Fear, anger, and tension can lead to digestive
difficulties
◦ Reducing stress and tension during mealtimes will
allow for better absorption of nutrients
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Food Allergies
◦ A food allergy is a reaction of the immune system
to certain proteins found in food
◦ The immune system protects the body from
invaders by forming antibodies
◦ When you are allergic to a food, your body releases
antibodies in response to that food, leading to
allergy symptoms
◦ These symptoms can include, but are not limited to,
vomiting, intestinal distress, rashes, and swelling
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This is different from a food sensitivity, such
as lactose intolerance
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Physical Activity
◦ Aids digestion and
metabolism
◦ Stimulates a healthy
appetite and strengthens
the muscles of the
internal organs
◦ Helps move food through
the GI tract
◦ Reduces stress
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A nutritious diet can help to avoid or manage
most digestive disorders
Some disorders require medical treatment in
order to make certain that all required
nutrients make it to the cells in order to
maintain life
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Diarrhea
◦ Frequent expulsion of watery feces
◦ Causes food to move through the digestive system
too quickly for nutrients to be absorbed
◦ Also leads to loss of body fluids as the food moves
too quickly through the large intestine for the water
to be reabsorbed
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Constipation
◦ Occurs when chyme moves too slowly through the
large intestine, leading to the reabsorption of too
much water
◦ Causes the feces to become too hard and dry,
which can lead to painful elimination and
hemorrhoids
◦ Often caused by erratic eating habits, low fiber
intake, lack of physical activity, and inadequate
fluid intake
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Indigestion
◦ Difficulty in digesting food
◦ Can be caused by stress, eating too much or eating
too fast, or eating particular foods
◦ Can include gas, stomach cramps, and nausea
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Heartburn
◦ A burning pain in the middle of the chest caused by
stomach acid flowing back into the esophagus
◦ Can be reduced by avoiding acidic foods, stress,
lying down right after eating, and taking antacids
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Ulcer
◦ An open sore in the lining of the stomach or small
intestine caused by bacterium
◦ Risk is increased by stress, heredity, alcohol use,
and aspirin abuse
◦ Usually treated with antibiotics, as well as
decreasing stress, alcohol, caffeine, and tobacco
use
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Gallstones
◦ Small crystals that form from bile in the gallbladder
◦ These stones block the release of bile into the small
intestine, causing pain and slowing the digestion of
fats
◦ Treatment includes a diet low in fats, and often
requires surgery to remove the gallbladder
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Diverticulosis
◦ The formation of abnormal pouches in the intestinal
wall
◦ Can occur when the intestinal muscles become
weak, such as when a diet is low in fiber
◦ These pouches can become inflamed, leading to a
painful condition called diverticulitis
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*What Could Be Wrong
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*Digestive Disorders